


How Deep the Sea

by DistractedDream



Category: Final Fantasy XV
Genre: Established Relationship, Gratuitous Smut, M/M, MerMay, Not Beta Read, Plot What Plot/Porn Without Plot, Tentacle Sex, Tentacles, birthday fic, gladnoct - Freeform, mer!Noct, mermaid au, octo!Gladio
Language: English
Status: Completed
Published: 2020-06-02
Updated: 2020-06-02
Packaged: 2021-03-03 20:48:11
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,286
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24501862
Author URL: https://archiveofourown.org/users/DistractedDream/pseuds/DistractedDream
Summary: Gladio and Noct sneak away during a training session for some alone time.And I learned more about the mating habits of octopi and dolphins to write this than I ever wanted to know.
Relationships: Gladiolus Amicitia/Noctis Lucis Caelum
Comments: 6
Kudos: 63





	How Deep the Sea

**Author's Note:**

  * For [SerenityXStar](https://archiveofourown.org/users/SerenityXStar/gifts).



> Hi there! I'm back again with my fourth birthday fic for SerenityXStar! Please wish her a happy birthday! This year features more GladNoct - but this time, they're merpeople! Well, Noct is a mer (though he has dolphin anatomy but with scales because I do what I want) and Gladio is an octopian/octoperson/listen... I learned way too much with this one.
> 
> Thanks to the FFXV Fae server for all the brainstorming and technical help! Song title from "How Do I Love Him?" by Sirena.
> 
> Comments and kudos are much appreciated and keep me writing! I can be found on [Twitter](https://twitter.com/distractedream) at Distractedream and [Tumblr](https://distracteddream.tumblr.com/), [Instagram](https://www.instagram.com/distracteddream/), and [Spotify](https://open.spotify.com/user/distracteddream?si=_Yuds57lRve_hXzKrEF05Q) at DistractedDream. Enjoy!

Amber tentacles encircled Noct’s tail and thick arms snapped closed around his chest, pulling the Prince flush against his Shield. “Is this a trap?” the mer asked as he squirmed against Gladio. Their training session had taken them farther afield than usual and Noct felt rather clever as he warped amongst the rocky outcroppings beyond the Walls of the Citadel. Or he had - right up until Gladio captured him from behind.

The octopian chuckled, his chest vibrating with the noise, long strands of hair floating around them as he propelled them backwards, deeper into the rocks until they were well hidden. “It’s only a trap if you don’t want to be here.” His hold loosened momentarily, tentacles resting on rather than gripping the mer. The offer was there; if Noct wasn’t in the mood, he could easily get away. “Figured you led me all the way out here for something. Might as well give it to you.” Gladio kissed Noct’s shoulder. “We’ve got time.”

“I didn’t lead you anywhere.” Noct clicked his teeth, ever the Brat Prince. “Ugh, you want to fuck again, don’t you? Is it mating season or something?” He didn’t think it was because Ignis would never have let Noct go off alone with the octopian if it were. Noct tipped his head to the side as Gladio began kissing his neck. He certainly had no intention of submitting, at least not while they sparred. If they were done practicing though, the mer could allow himself to enjoy the feel of Gladio’s bulk surrounding his smaller form. 

The octopian’s arms and tentacles squeezed around him once more. “Nah, it’s just what you do to me. Watching you swim laps around me. Seeing how strong you’re becoming.” Noct huffed. “It’s true,” Gladio insisted. His tentacles slipped up and down Noct’s tail, from the slight curve where scale met skin to where it tapered down before spreading wide into blue-black fins. He smoothed his palms over Noct’s chest, feeling the mer’s heart pounding under his hand. The muscles of the Prince’s tail expanded and contracted within Gladio’s tentacles as Noct lazily worked to keep them afloat. “You’re gorgeous.”

“And you’re horny,” Noct retorted. The octopian merely hummed against his skin, too busy appreciating his Prince to respond. “You know you could get into a lot of trouble touching me like this.” Noct put on his best Ignis-voice. “A prince is supposed to be pure. Untouched. A-” The mer gasped as Gladio effectively silenced him by attaching suckers low across his belly and the sensitive skin there.

“A what?” The Shield prodded when he felt Noct start to go lax in his grasp. He nibbled at Noct’s ear fin. “A virgin? That’s funny. That ship has sailed, hasn’t it?” Another tentacle lifted higher, Gladio shifting his hold, a double row of suckers latching onto Noct’s chest across his nipples. “Six, Noct,” he groaned low, his receptors catching tastes of his Prince’s skin.

The mer’s spine arched, pressing his chest up into the contact. “Marks,” he warned though he hated to do so. Noct wanted the little round bruises that would fade black and blue, complementing his tail colors. He wanted to be left with a visual reminder of being with Gladio. But though he suspected Ignis knew he’d taken Gladio as a lover, the rest of the Citadel didn’t and it needed to stay that way. For now. His fins swished as Gladio’s tentacles glided lower over his scales appreciatively, his fingers brushing lightly over them.

Gladio’s fingers replaced his suckers, pinching and rolling Noct’s nipples, making him whimper. “That better?” Noct let his head fall back onto his Shield’s shoulder, his nipples hardening at the attention. A soft whine was his only answer. Gladio grinned, sharp teeth teasing along the joint of Noct’s shoulder. He utilized all his Prince’s erogenous zones better each time they did this, memorizing what places or what type of touch would turn the mer pliant and eager. “One day, I’m gonna lay you out all proper and fuck you until you can’t swim straight.”

“You talk a big game.” Noct’s thready wanton tone betrayed his sassy words. He popped his hips, rubbing along the web between Gladio’s tentacles where it was stretched open from the Shield’s hold. The octopian’s muscles constricted around Noct involuntarily, a shudder striking him. “But can you back it up?” the Prince taunted.

Gladio leaned back to allow enough space between them to fit his hectocotylus, the lengthy tentacle with a distinct tip serving as his cock. He rubbed it over Noct’s backside and spine, rendering the mer silent again. “Yeah, I can,” Gladio purred into his ear. He dragged the phallic appendage around Noct’s ribcage and over his chest. The grooves tickled Noct’s flesh as more of Gladio’s tentacles started massaging Noct’s hips and tail, edging closer to his genital slit. The Shield’s skin flashed, black lines appearing and disappearing over him as his motions became more deliberate. His back would be covered in the dark lines, he knew; the pattern served as a warning to others that he’d claimed the mer as a mate. Noct’s fins flicked harder, but when he opened his mouth to object to the teasing, Gladio inserted his hectocotylus between his lips.

Noct moaned, mouth closing around him, licking the tip of his tongue along the grooves. Gladio panted against Noct’s neck, his suckers latching possessively onto his Prince. Noct opened his jaw, letting Gladio control the slide of his dick along his tongue. His tentacles prodded at the mer’s slit, tips slipping into the fold, encouraging his cock from its sheath. “Come on, Noct,” Gladio purred. “Show me how good you are for me. Let me feel it.” His suckers connected above and below Noct’s fold, manipulating the area to relax so his cock would protrude. “Come on, baby.”

With a muffled sigh around Gladio’s dick, Noct felt his slit stretch, his cock extending into the water. Gladio withdrew his hectocotylus, his chest rumbling with approval. “There you are.” As eager as he was to thrust into the mer’s opened body, the Shield held himself back. Instead, he used two tentacles to envelope Noct’s cock, suckers sealing themselves to his skin. Noct’s back bowed, crying out at the feeling of the muscles clinging to his cock. Gladio spread his hands over his chest and hips, holding Noct tightly to him. “I’m gonna mark you. Here. Where nobody else is gonna see. And tonight, when you’re jacking off in bed, you’ll see my marks on you and remember my touch.” The Prince whined, bracing a hand on the nearest rock, his fins moving faster. Gladio rubbed a tentacle over the tip of Noct’s cock, the suckers pulling at his slit as the tentacles writhed around him. The Shield groaned. “Six, baby, you taste so damn good.”

He was going to lose it. Noct was going to cum. There was no point in trying to fight the urge. His hips bucked forward. Faster. Harder. Gladio’s tentacles engulfed his cock completely. His heart was rioting, fingers scraping at the rock, pleasure coiling tighter and tighter. Gladio’s suckers latched onto him and pulsed and Noct was gone. Release spiked through him with another snap of his hips, ejaculate slipping between the octopian’s tentacles to cloud the water before Noct’s hips.

Gladio let him come down with gentle kisses to his temple, his tentacles releasing Noct’s still erect cock. They moved to his slit, dipping the tiny ends between the fold, checking. “You’re so good, baby. You’re gonna let me in, yeah? Gonna be good for me?” Noct nodded, twisting his upper body to kiss his Shield. As much as he loved watching himself disappear into Noct’s fold, Gladio couldn’t break away from his Prince’s gaze. Their open mouths brushed together as Gladio’s tentacles helped prop the mer’s cock higher, allowing his hectocotylus to nudge into his slit. As Gladio pushed in, Noct shuddered, eyes rolling back as another orgasm struck him.

“I got you, baby.” Gladio kept Noct in his embrace, waiting until his heart stopped racing quite so much before inserting his dick deeper. Noct rolled his hips and Gladio tensed the muscle for Noct to frot the internal portion of his cock against him. He curled the tip up, feeling his way into his Prince’s body. “Gonna cum again for me? I know you can.” Gladio wouldn’t lie; mer physiology might allow Noct to repeatedly orgasm in quick succession, but it was Gladio who got him there and that was one hell of a rush. He kept the pressure up, letting Noct’s hips move, nipping at his parted lips. “Cum,” he growled.

Noct whimpered at his third orgasm, the octopian’s tentacles cradling his cock as it pulsed. “Gladio…” They stayed joined while Noct caught his breath, Gladio’s touch and kisses turning gentle so the mer could recuperate. Once his heart didn’t feel like it would jump out of his chest, Noct straightened himself, his head dropping forward. Gladio rested his chin on Noct’s shoulder, finally able to watch himself fuck his Prince. Noct knew Gladio had voyeuristic tendencies but for him it was almost too much to see it happening. The first time he had, the mer had clouded the water so badly that they had to swim against the current for fresh water. Gladio’s dick thrust slowly into him, pulling almost completely out before plunging in again. Rumors were that Gladio was quick fuck and Noct had laughed aloud at that. On the contrary, the octopian was a thorough lover, bringing Noct to the peak over and over again before seeking his own release. 

He could almost rest, could almost doze off while he let Gladio fuck him. The octopian would get enchanted by the way the mer’s slit opened for him, by the way his darkened appendage was swallowed between the darker scales, fucking him for over an hour. He had fallen asleep once, his soft snoring breaking the spell and the moment though Noct had insisted that Gladio hadn’t needed to stop. They’d finished in Noct’s mouth that time, but the mer was still keyed up from their sparring right now; there’s be no sex-naps today. And he definitely didn’t want Gladio to finish anywhere but inside him.

Noct reached up, cupping the side of Gladio’s head, stretching back to let him get a better view. His other hand smoothed over his Shield’s tentacles, caressing his skin, positioning him directly above his genital slit. Gladio’s suckers connected to his scales, little pulsating suckles adding pressure above Noct’s cock. The Prince moaned, his muscles contracting around Gladio. “Yeah, just like that. I want… fuck, Gladio, I want…”

“What do you want, Noct?” Gladio’s attention diverted from where they were joined to Noct’s face, watching it contort in pleasure. He sucked harder at his scales, drunk on the taste of him. “Tell me what you want.”

“I want…” Noct’s sharp little teeth bit down on his bottom lip as he wriggled. His dark blue eyes seemed even darker with the pupils blown wide. “I want you to cum in me.” Gladio’s appendage flexed inside Noct at the words, his markings flashing jet black. He didn’t need to say anything; his body communicated well enough. The mer’s cock throbbed as his fingers slipped along where their bodies were connected. He flicked his eyes to Gladio’s to find them locked on him. “Fill me up.”

Gladio trembled, wrapping himself entirely around Noct. His suckers worked the mer’s cock as he thrusted into him. His arms and tentacles braced his Prince, the rough pounding pushing him back. Noct’s fins flapped harder to keep them in place, pulling himself forward onto Gladio’s dick and squeezing the muscles around him. “Gla-ah-dio…” Noct’s voice broke as Gladio fucked him right back to the edge of completion. “ _ Gladio _ !” the Prince cried out, stiffening as he came again. Gladio’s suckers covered the slit of his cock, the taste of Noct’s cum being the last push the Shield needed. With a shout, Gladio convulsed, releasing his sperm packets within his Prince.

They dropped lower in the water as Noct’s fins slowed, beginning to feel the weariness of multiple orgasms. The octopian disentangled enough tentacles to help propel them upwards again. Together, they coasted on the current among the rocks, basking in the afterglow, nuzzling each other and trading soft kisses. Gladio withdrew slowly, hooking his hectocotylus carefully to scoop out as much mess as he could. He chuckled as Noct made a face. “Iggy’d kill me if he found you sleeping surrounded by my sperm later.”

“Might be worth it,” the mer mused, yelping as Gladio flicked his oversensitive cock.

“Tell ya what. Come camping with me,” Gladio offered. Noct scowled, side-eying the octopian. “I’ll show you an awesome place to go humaning. You can catch as many as you want.” He brushed Noct’s hair back, kissing his head. “And when you’ve had your fun, I’ll fill you up again and let you fall asleep stuffed with me. Deal?”

Noct’s expression brightened, teeth glinting as he smiled. “Oh, totally. It’s a deal.” He turned carefully, mindful of his still extended cock. “But I’m not finished with you yet.” By the time Gladio had brought Noct to orgasm twice more with his hands and mouth, the mer was practically dead weight in the water, flopping into Gladio’s arms.

The Prince tucked himself against Gladio’s chest as the octopian propelled them through the water back toward the Citadel. They would need to separate before they were in sight of the Walls, but for now, Noct clung to his Shield, dreaming of their promised trip and of falling asleep in Gladio’s arms.


End file.
